Defect. Motor Coach Industries (MCI) is recalling certain 2018-2020 D4000, D4005, D4500, D4505 and D45CRTLE buses manufactured with electric cooling fans (E-fan) for the radiator and charge air cooler, Borg Warner 55SI model dual alternator configuration (with a sense stud and wire), and Parker Vansco Multiplexing Module (VMM) Multiplex system. A build-up of debris, corrosion, and/or water flow could cause a high resistance path to ground for the sense stud on the back of the alternator and cause the alternator to produce excessive voltage output, which may exceed the threshold limit currently programmed in the VMM and result in a loss of engine power and vehicle shutdown.
Risk. If the engine shuts down or loses power while the vehicle is in motion, this may increase the risk of a crash.
Remedy. MCI will notify the affected owners, and dealers will install a new application code in the Parker VMM multiplex modules increasing the overvoltage threshold limit, free of charge. The recall began July 23, 2020. Owners may contact MCI customer service at 1-800-241-2947. MCI's number for this recall is SB 479.